Reply to OH Holmqvist

Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, E-mail: frank.hu{at}channing.harvard.edu

As shown in Table 1 of our article (1), protein intake, especially animal protein, is positively associated with saturated fat because major sources of protein such as red meat also contain high amounts of saturated fat. Therefore, our multivariate analyses controlled for saturated fat intake. We previously published results on saturated fat intake and risk of coronary heart disease in the Nurses' Health Study (2). In this study, 5% of energy from saturated fat, compared with an equivalent amount of energy from carbohydrates, was associated with a nonsignificant 17% greater risk of coronary disease (relative risk: 1.17; 95% CI: 0.97, 1.41; P = 0.10). In metabolic studies, replacing carbohydrates with saturated fat increases not only plasma LDL cholesterol, but also HDL cholesterol (3). The weak effect observed in prospective studies is consistent with the possibility that the proportional increase in plasma HDL-cholesterol concentrations produced by saturated fatty acids largely compensates for the adverse effects of these fatty acids on LDL concentrations.

REFERENCES

1. Hu FB, Stampfer MJ, Manson JE, et al. Dietary protein and risk of ischemic heart disease in women. Am J Clin Nutr 1999;70:221–7.
2. Hu FB, Stampfer MJ, Manson JE, et al. Dietary fat intake and risk of coronary heart disease in women. N Engl J Med 1997;337:1491–9.
3. Mensink RP, Katan MB. Effect of dietary fatty acids on serum lipids and lipoproteins: a meta-analysis of 27 trials. Arterioscler Thromb 1992;12:911–9.